El Unbral (Sangre de la trilogia del cielo #2)

Brandon Martus is a confused young man struggling to cope with his unresolved grief over his sister's death and his father's paralysis. Then Martus meets neurobiologist Sarah Winerraub, who is performing research into parapsychology at the Moran Research Institute in town. Winerraub believes Martus has extrasensory abilities and coerces him into participating in her research. She is at first thrilled when he shows intense psychic abilities. Soon, however, both Martus and Winerraub find themselves in a fight between good and evil.